This invention relates to portable rotary drills, and particularly to drills which are adapted to collect and retain the cuttings or chips formed by the drill bit in use.
In some situations in which hand drills are used, problems of serious magnitude can be encountered if the cuttings produced by the drill bits are allowed to remain in the vicinity of the work. For example, when drilling operations are performed during the assembly of an aircraft, chips formed by the drill may fall into an electrical "harness" or other wiring assembly, to positions at which the sharp edges of the chips may cut through the insulation of the wiring under the effect of vibrations encountered when the plane is in flight. In this or any of various other ways the chips may directly or indirectly cause short circuits in the wiring of an aircraft or the like, which may ultimately result in a serious accident or damage to the equipment. In other instances, the chips may fall into a sealant material, adhesive, or other substance, which subsequently cures or dries to a hardened condition in which it may permanently retain the cuttings at locations leaving their sharp edges exposed for contact with clothing, persons or equipment which might be damaged by the sharp edges. Even where actual harm may not result from the cuttings, it is still desirable in aircraft to remove the cuttings, if only for the purpose of eliminating excess weight on the craft. In other non-aircraft drilling situations, as for instance in and around a home or business establishment, cuttings produced by a drilling operation may be inconvenient to remove, and often detrimental to carpets, drapes, or other furnishings.
There have in the past been proposed various types of drills in which a suction effect has been utilized for withdrawing cuttings produced by the drill bit to a bag or other accumulation receptacle. For example, in U.S. Pat. Nos. 2,339,324, 2,246,916 and 2,349,156, there is shown a type of arrangement in which a housing is disposed about the chuck and bit of a drill and is connected by a flexible hose to an aspirator and collection bag formed separately from the drill, with the aspirator serving to draw air and entrained chips from the location of the bit into the bag. Similarly, U.S. Pat. No. 1,955,182 shows a boring machine having a motor driven fan which creates a flow of air to remove cuttings. Other drill devices having suction systems are shown in U.S. Pat. Nos. 994,430 and 3,351,143.
Each of these prior suction type devices of which I am aware has had one or more disadvantages inherently limiting its practical usefulness in an actual industrial or commercial environment. For example, one very serious disadvantage of all of these devices has resided in the extremely cumbersone character of the suction equipment, necessitating the provision of space in the vicinity of the drilling operation for reception of a separate chip collection bag or the like, which bag must in most instances be handled separately from the drill itself, thus precluding use of the drill in many of the confined spaces in which drilling must be performed in the assembly of an aircraft. Such separately formed suction equipment must also be relatively expensive to manufacture, and increase the cost of the overall drilling assembly to a point rendering it impractical for many uses. In addition, in most instances the suction equipment has required separate controls, needlessly complicating the operation of the equipment by requiring the suction equipment and the drill proper to be turned on and off separately at each use.